Brown: Honda are having a good test and good on them

McLaren had some teething problems with their new Renault power unit and their new MCL33 package in general, but the team puts it down to minor gremlins which they are addressing during the test.

Casting an eye to the Honda progress during testing at Circuit de Barcelona-Catalunya, Brown was magnanimous in his praise of their former engine supplier, "I think they're doing a good job."

"We're focused on our own programme. I know, as you'd expect, there are a lot of comparisons in testing between them and us, but Eric [Boullier] and the full team are focused on our programme, and very confident we're going to have a good season."

"We know they're a great company and it was just a matter of time until they'd see some improvements. They're having a good test and good on them," acknowledged Brown

Toro Rosso-Honda have made impressive progress, their drivers Brendon Hartley and Pierre Gasly completing 666 laps of testing compared to the 506 laps covered by McLaren-Renault drivers, with one day of testing remaining before the season-opening Australian Grand Prix at the end of the month.

Meanwhile, McLaren's Stoffel Vandoorne was sixth-fastest and covered 151 laps on Thursday – the most laps the team have completed during a single pre-season test day in this fifth year of the V6 hybrid era.